Evaluation of the visual system within the context of neuropsychiatry has revealed that psychoactive drugs do affect the retinal function of humans. Metoclopramide, L-dopa, benzodiazepines, and morphine each have an individual effect. In addition, midline dysgenesis in patients with Kallmann syndrome has been investigated. Patients show a higher incidence of congenital color vision loss than expected in the normal population, iris midline defects are present (not previously described), synkinesis was demonstrated in a large percentage of patients, and eye movement disorders have been characterized.